LONG TERM GOALS

Develop Circular Synthetic Aperture Sonar (CSAS) techniques and signal processing algorithms to generate high resolution acoustic images of mine and non-mine targets using bistatic and multistatic sonar configurations. OBJECTIVES The objective of this work is to demonstrate the feasibility of Autonomous Underwater Vehicle (AUV) based bistatic CSAS imaging of bottom mines and mine-like targets, to evaluate and compare the quality of bistatic imaging relative to monostatic imaging, and to determine the practical advantages (or disadvantages) of bistatic imaging with respect to monostatic imaging. APPROACH Most synthetic aperture sonar (and radar) systems operate in a monostatic mode in which the source and receiver are collocated. To generate a monostatic CSAS image, the target region is partially or completely circled by the sonar and echoes are acquired over a large range of target aspects. Detailed images of target outlines can be produced from this data even at relatively low transmit frequencies (tens of kHz) [1,3]. In the bistatic mode, the source and receiver are separated in space and the geometry considerations are somewhat more complicated [2,3]. Under this task, bistatic CSAS imaging algorithms have been developed as extensions to the monostatic CSAS imaging algorithms previously developed at ARL:UT. Bistatic CSAS image processing is based upon Fourier Transform reconstruction techniques similar to those in [4-6] with significant modifications to accommodate the bistatic configuration [1,3].